Hydraulic jack systems



United States Patent 3,381,589 HYDRAULIC JACK SYSTEMS Hew Dalrymple Fanshawe, Edinburgh, Scotland, assignor to F.N.R.D. Limited, London, England, a British company Filed Sept. 17, 1964, Ser. No. 397,085 Claims priority, application Great Britain, Sept. 19, 1963, 36,987/63 6 Claims. (Cl. 92-112) This invention relates to hydraulic jack systems of the kind in which a cylinder member is arranged to move in relation to a piston member. The invention relates in particular, though not solely, to systems in which the throw of the jack is more than, say, ten times the diameter of the piston.

In such long throw systems it is frequently necessary that the reactive force of a jack upon the fixed or moving structure should be supported 'with a limited degree of angular flexibilityfor instance, in order to prevent bending forces upon the jack resulting from lateral or angular deflections of the loaded structure. In consequence, feed ducts for feeding actuating fluid to the piston are required to have a certain degree of flexibility, and it has normally been deemed necessary to provide flexible pipes at some point in each feed duct. Such pipes and their couplings, for the more powerful jacks, become extremely massive and expensive, particularly if they have to be capable of withstanding appreciable hydraulic pressures, which for relatively slender jacks must inevitably follow; and the more slender the jack, the greater the need for provision for flexibility.

The present invention provides for relatively simple and effective means of attaining such flexibility while yet dispensing with the necessity for the flexible pipes.

The invention is applicable to systems in which hydraulic actuating fluid is fed only to a space in contact with the operating face of the piston to cause extension of the jack, retraction of the jack taking place when the actuating fluid passes out of this operating space, say, by expulsion under the weight of the cylinder after operation of suitable valves; it is also applicable to systems in which arrangements have to be made for the feed and return of hydraulic actuating fluid to. and from spaces in contact with oppositely effective surfaces of the piston.

In accordance with one aspect of the invention, in an hydraulic jack system of the kind referred to, the piston member is provided with a hollow stem member to enable actuating fluid to be fed to the operating face of the piston member for causing extension of the jack, a hollow universal-pivot type mount for said stem member being provided through which said fluid is arranged to pass and a bolt member fixed in relation to the stern member being arranged to co-operate with anchoring means fixed in relation to said pivotal mount to hold said stem member onto the mount. Said piston member may be arranged for sealed connection to one end of its said stern member, one part of said bolt member being attached to the piston member so that, in holding the stern member onto the pivotal mount, it also acts to hold said piston member onto the one end of the stem member.

In accordance with another aspect of the invention, in such a system a hollow bolt member is fixed in relation to said piston member and provides passage to an bydraulic connection in said piston member to an operating face for causing retractive movement of the jack, said bolt member passing through a hollow stem member for the piston and a hollow mount of the universal-pivot type for said stem member, to anchoring means fixed in relation to said pivotal mount, actuating fluid for causing extension of the jack being arranged to be fed through said hollow stem member and said hollow mount.

ice

The said hollow bolt member may be in the form of a tube screwed at one or both ends or one end and near the other end.

For the long-throw type of system, the cross-section and length of the stem member and/ or of the bolt member may be arranged to provide sufiicient flexibility to enable ample pivotal movement between the parts of the joint. If necessary, however, the bolt member may include a universalpivot type of point, to give greater flexibility in case the stern member and cylinder tend to flex excessively.

One embodiment of the invention in an hydraulic jack system suitable for use vertically with an earth drilling rig of a kind similar to that disclosed, for instance, in Britist patent specification No. 875,127, that is to say wherein the jack system may serve to operate lifts for a drill pipestring, will now be described by way of example with reference to the accompanying part-sectional drawmgs.

In the drawings FIGURE 1 shows a type of system with a solid bolt member while FIGURE 2 shows a double acting type of system.

In FIGURE 1, the jack system comprises a hollow support 1 with passage 2 for hydraulic actuating fluid to be passed under control of suitable valves to and from the face So of a piston 3 via holes 4 in the piston, for extending the jack. The valves will permit of venting of the fluid, and the fluid might even be vented under suction, for retraction of the jack. The base support 1 is arranged to be carried by the structure of the drilling rig. The piston 3, which carries a plurality of sets of sealing rings as indicated, co-operates with one end of a stem tube 5, the other end of which is supported by a spherical-type mount 6 on the support 1 so as to permit of movement of the jack to take up degrees of misalignment of gear being moved; this misalignment would of course normally be kept to a minimum. Co-operating with the piston and stem tube assembly is a cylinder 7 with packing 8 at it lower end as shown. A bolt member in the form of a slender rod 20 of adequate strength, is secured at one end to the piston 3 and at the other end to the support 1, it being screwed at one or both ends so that is draws the piston onto the end of the stem tube 5 and, in consequence, the stem tube is pulled onto the face of the mount 6. The rod is tensioned to ensure that a fluidtight joint is made on a seal 14 in the face of the mount under all operating conditions.

It will be appreciated that, the stem tube 5 of the jack being only about eight inches in diameter and the jack having a throw of approximately twenty feet, the drawing has been foreshortened; in the extended state, therefore, there will be a considerable tendency for the jack to flex about the reaction point which is at the joint 6. Shaping of the joint 6 permits of sufficient flexing and the consequent movement of the piston is permitted by virtue of flexibility of the bolt member.

In the double-acting type of jack system shown in FIGURE 2, where the piston is hydraulically actuated in both directions, parts similar to those described above with reference to the arrangement shown in FIGURE 1, are depicted using the same reference numerals. In this system, however, there is a definite space 9 between the inner wall of the cylinder 7 and the stem tube 5 and this connects with face 3b of the piston; ducts 10 and 11 are provided for feeding actuating fluid to and from this space 9.

In this double-acting arrangement, the bolt member takes the form of a hollow tube 12 of adequate but comparatively small wall thickness, and this tube is screwed at one end to the piston to form a feed to duct 11 therein. The other end of the tube 12 is secured to a seating 13 in the support 1 and, as in the case of the rod in the arrangement of FIGURE 1, this tube 12 is O tensioned to ensure a fluidtight joint at the sealing ring 14 under all reasonable operating conditions.

The passage from the piston continues through tube 12 to a. rigid connection 15 which in turn is connected to a source of pressurised actuating fluid through suitable valve gear, as will be well understood. The connect-ion 15, as also the connection to passage 2 (this latter in the previous example also), can be simple rigid couplings.

In both figures, as shown, the piston is given a buffer extension 16 which co-operates with the end 17 of the cylinder 7 to slow down movement of the cylinder in the, retractive direction.

If desired, and certainly if flexing is to be excessive, it may be arranged that the rod member 20 or the tube member 12 may have a universal-pivot type of joint and such is indicated in ghost outline at 21 in FIGURE 1. Other modifications within the spirit of the invention will be apparent to those skilled in the art.

In both figures, the cylinder 7 is shown as being formed at its inner end with a breech-block type of fixation 18 for a member 19; this member 19 may be part of a lift system for an oil drilling rig, and the feature of this form of fixation is that it may be discontinuous around the circumference of the cylinder so as to be capable of rapid engagement and disengagement by a simple rotary movement.

I claim:

1. An hydraulic jack system comprising a piston memher, a cooperating cylinder member movable relatively to said piston member, a hollow stem member of substantially the same diameter as said piston member having one end in abutment with said piston member, a hollow support having a universal-pivot type mount on which the other end of said stern member is supported, means including said hollow stem member and said hollow mount providing a fluid connection to one operating face of said piston for causing extension of the jack, a flexible hollow bolt member of substantially smaller diameter than said piston member, one part of said bolt member being fixed to said piston member and providing passage to an hydraulic connection in said piston member to another operating face thereof for causing retractive movement of the jack, and means for anchoring another part of said bolt member to said support so that said bolt member is under tension, said bolt member passing through said pivotal mount and said stem member to said anchoring means and acting to hold said stem member onto said pivotal mount and at the same time to provide connection for actuating fluid to the other operating face of the piston member for retraction of the jack.

2. An hydraulic jack system as claimed in claim 1, including means for forming a sealed connection between said piston member and the abutting end of said stem member.

3. An hydraulic jack system as claimed in claim 1, wherein the lengths of said piston member, stem member, bolt member, and cylinder member are such that the maximum throw of the jack is in excess of ten times the diameter of the piston.

4. An hydraulic jack system as claimed in claim 3, wherein said bolt member includes a universal-pivot type joint intermediate its ends for greater flexibility thereof.

5. An hydraulic jack system comprising a piston member, a cooperating cylinder member movable relatively to said piston member, a hollow stem member of substantially the same diameter as said piston member having one end in abutment with said piston member, a rigid hollow support having a universal-pivot type mount on which the other end of said stem member is supported, means including said hollow stem member and said hollow mount providing a fluid connection to the operating face of said piston for causing extension of the jack, a flexible bolt member of substantially smaller diameter than said piston member having one end fixed to said piston member, means for anchoring the other end of said bolt member to said support, and means for tensioning said bolt member so as to hold said stem member onto said pivotal mount, the lengths of said piston member, stem member, bolt member and cylinder member being such that the maximum throw of the jack is in excess of ten times the diameter of the piston member.

6. An hydraulic jack system as claimed in claim 5, including means for forming a sealed connection between said piston member and said stem.

References Cited UNITED STATES PATENTS OTHER REFERENCES 1,129,911, German printed application (Bergbautechnik), May 1962.

MARTIN P. SCHWADRON, Primary Examiner.

I. C. COHEN, Assistant Examiner. 

1. AN HYDRAULIC JACK SYSTEM COMPRISING A PISTON MEMBER, A COOPERATING CYLINDER MEMBER MOVABLE RELATIVELY TO SAID PISTON MEMBER, A HOLLOW STEM MEMBER OF SUBSTANTIALLY THE SAME DIAMETER AS SAID PISTON MEMBER HAVING ONE END IN ABUTMENT WITH SAID PISTON MEMBER, A HOLLOW SUPPORT HAVING A UNIVERSAL-PIVOT TYPE MOUNT ON WHICH THE OTHER END OF SAID STEM MEMBER IS SUPPORTED, MEANS INCLUDING SAID HOLLOW STEM MEMBER AND SAID HOLLOW MOUNT PROVIDING A FLUID CONNECTION TO ONE OPERATING FACE OF SAID PISTON FOR CAUSING EXTENSION OF THE JACK, A FLEXIBLE HOLLOW BOLT MEMBER OF SUBSTANTIALLY SMALLER DIAMETER THAN SAID PISTON MEMBER, ONE PART OF SAID BOLT MEMBER BEING FIXED TO SAID PISTON MEMBER AND PROVIDING PASSAGE TO AN HYDRAULIC CONNECTION IN SAID PISTON MEMBER TO ANOTHER OPERATING FACE THEREOF FOR CAUSING RETRACTIVE MOVEMENT OF THE JACK, AND MEANS FOR ANCHORING ANOTHER PART OF SAID BOLT MEMBER TO SAID SUPPORT SO THAT SAID BOLT MEMBER IS UNDER TENSION, SAID BOLT MEMBER PASSING THROUGH SAID PIVOTAL MOUNT AND SAID STEM MEMBER TO SAID ANCHORING MEANS AND ACTING TO HOLD SAID STEM MEMBER ONTO SAID PIVOTAL MOUNT AND AT THE SAME TIME TO PROVIDE CONNECTION FOR ACTUATING FLUID TO THE OTHER OPERATING FACE OF THE PISTON MEMBER FOR RETRACTION OF THE JACK. 